Relief valve apparatus

ABSTRACT

A tamper proof safety relief valve having both a basic relief valve and a safety relief valve capability incorporated therein. The relief valve is adapted to open a valve port when a predetermined pressure is applied thereagainst and a tamper proof safety relief element is adapted to open a valve port through said relief valve when a predetermined pressure is reached. If the basic relief valve fails to operate, the safety relief element will come into operation at a pressure just beyond the operating pressure of the basic relief valve.

United States Patent [1 1 Appl. No.: 142,312

Frankewich 1 Jy 31, 1973 [5 RELIEF VALVE APPARATUS 2,704,035 3/1955Bader 137 5122 x [76] Inventor: Peter A. Frankewich, RR. 2, Box

372 Daytona Beach 32019 Primary ExaminerMartin P. SchwadronAttorney-Duckworth & Hobby [22] Filed: May 11, 1971 [57] ABSTRACT Atamper proof safety relief valve having both a basic relief valve and asafety relief valve capability incorporated therein. The relief valve isadapted to open a valve port when a predetermined pressure is appliedthereagainst and a tamper proof safety relief element is adapted to opena valve port through said relief valve when a predetermined pressure isreached. If the basic relief valve fails to operate, the safety reliefelement will come into operation at a pressure just beyond the operatingpressure of the basic relief valve.

1 Claim, 3 Drawing Figures i If RELIEF VALVE APPARATUS BACKGROUND OF THEINVENTION The present invention relates to relief valves and especiallyto relief valves adapted for use with pressure type systems such asboiler configurations, hydraulic devices, and chemical processing andpneumatic sys terns to relieve pressures exceeding the operatingcapability of the equipment.

In the past many types of relief valves have been provided for use inboilers, and similar systems and to provide relief in the event pressureexceeds predetermined levels to prevent such equipment from exceedingthe pressure limits within which it was designed to operate and therebycreating a dangerous situation by the high pressure.

These safety valves for letting out excess pressure typically havespring or lever operated lids fitting tightly in a seat of the sameshape. The valves open when pressure reaches a danger limit, andfrequently may be adjusted to operate at desired pressure levels bychanging the spring or the weight of a lever. The relief valve is aspecial form of safety valve and usually has a heavy spring biasing adisc, gate, plug or lid against a valve seat to block a passagewaythrough the valve from an inlet port to an outlet port through the valveport. The spring may be adjusted by a spring cap so that when thepressure in an apparatus reaches a predetermined or dangerous level, itwill push the valve disc against the spring to unseat the disc to allowthe escape of a fluid through the valve port and out the outlet. Thesevlaves have been satisfactory in operation but mechanical damage to thevalve or damage caused by an environmental condition, or even bytampering with the valve, can result in failure of the basic reliefvalve which may result in failure of the pressure equipment producingunsafe conditions for operating personnel. In high pressure operations,safety codes generally provide that such equipment have at least twovalves, each directed towards operation within a few psi of each other.

To overcome this problem, it is accordingly one object of the presentinvention to provide a basic relief valve having a tamper proof safetyrelief element providing the advantages of a pair of safety reliefvalves but in which the safety elements are tamper proof, and which unitis provided in a single valve casing.

SUMMARY OF THE INVENTION The present invention relates to safety valvesand especially to safety relief valves adapted to open uponpredetermined pressure levels being reached in an apparatus to which thevalve is connected and has a casing adapted for connection to anapparatus operating under pressure. The casing has a first gate meanslocated therein for blocking the passageway through the valve, whichgate is maintained in a valve seat by a predetermined pressure appliedto one side thereof. A second gate means located inside the valve casingis maintained in a valve seat located in the first valve gate and blocksa pressure port through the first valve gate. Both valve ports openpassageways through the valve and out the valve outlet whereby pressureapplied to a pressure port will normally open the first valve port uponthe pressure reaching a predetermined level, but if the first port failsto open, a slight rise over the predetermined pressure level for thefirst gate will operate the second valve gate to open the second valveport through the first valve gate to relieve the pressure being appliedto the valve. The valve provides for adjusting the operating pressure ofthe basic relief valve as well as the tamper proof safety relief valveportion.

Brief Description of the Drawings Other objects, features and advantagesof this invention will be apparent from a study of the writtendescription and the drawings in which FIG. I shows a cutaway sectionalview of one embodiment of the present invention in a closed position;

FIG. 2 is a sectional view of the embodiment of FIG. 1 with the basicrelief valve in an open position; and

FIG. 3 is a sectional view of the embodiment of FIGS. 1 and 2 with thetamper proof safety relief valve section in an open position.

Description of the Preferred Embodiment Referring now to FIGS. 1, 2 and3 of the drawings, a safety relief valve 10 can be seen having a casing11 with a threaded top portion 12 at one end and a pressure port 13 atthe other end thereof. A cap member 14 is threaded onto the top portion12 and an outlet port 15 is connected to the casing 11. The valve 10 isclosed in its normal operating position and is set to operate upon thepressure in the pressure port 13 reaching a predetermined level forwhich the valve has been set, thereby opening the pressure port torelieve the pressure, allowing the fluid which may be a gas or liquid,under pressure to escape through the outlet port 15 until the pressureagain drops below the predetermined level at which point the valve willclose itself. The operation of the valve provides a coil spring 16located inside the casing 11 and held at one end of a spring cap oradjustment member 17 which has a threaded portion 18 provided into thethreaded top 12 of the casing 11. The spring cap 17 has a bottom portion20 which engages the spring 16 at one end thereof. Passageway 21 passesthrough the spring cap 17 and has a rod 22 passing therethrough andadapted to slide therein. Spring 16 is biased against spring holdingmember 23 located at the other end of the spring from the spring holdingcap 17 which cap 23 also has rod 22 pushed thereagainst. Spring holdingmember 23 is pressed against gate assembly 24 which gate is sometimesreferred to as the disc, gate, plug or lid, depending upon the shape ofthe assembly, but the gate assembly 24 fits into a valve seat 25 forsealing a valve port 26 which blocks the passageway from 27, whichpasses from the pressure port 13 through the valve port 26 and out theoutlet I5 when the valve is in an open position, as can be seen in FIG.2. When a predetermined pressure is applied against the gate assembly24, the bottom portion 28, the pressure will overcome the spring 16pushing the whole valve assembly 24 into an open position and allowingthe fluid under pressure tpass through the valve port 26 and out theoutlet 15 as shown by the arrows in FIG. 2. The valve gating assembly 24has a tamper proof safety relief valve assembly 30 located thereinincluding a threaded top adjustment 3] for the assembly 24, whichthreaded top 31 is the cap for a spring 32 which spring 32 biasesagainst a second valve gate 33, which valve slides within the openportion 34 of the valve assembly 24 and closes against a valve seat 35to block a valve port 36 preventing the fluid under pressure frompassing from a pressure port 37 through the valve port 36 throughapertures 38 in the walls of the valve assembly 24 and out the outlet15, forming a second passageway through valve 10. In operation, as canmore clearly be seen in FIG. 3, if the basic valve fails to operate thepressure in the pressure port 13 and also in the pressure port 37 willapply pressure against the bottom 40 of the gate 33, and the tamperproof safety relief valve 30 will force the gate 33 against the spring32, lifting the gate 33 upon a predetermined pressure being reached,opening the valve port 36, as shown by the arrows to allow the fluidunder pressure to escape through the openings 38 and out the outlet 15.In a typical operation, the basic relief valve may be set to operate atl-psi and the tamper proof safety relief valve may be set to operate atl -psi in a system in which the perssure should not exceed l-psi. If thepressure reaches llO-psi without having opened the basic relief valve10, the auxiliary or tamper proof safety relief valve will be opened toprevent the pressure from reaching the l25-psi level. The basic reliefcomponents of the valve can be adjusted by removing the seal cap 14,loosening a lock nut 19 and adjusting the threaded top portion 17 tofurther compress the spring 16. However, the tamper proof or safetyvalve element 30 cannot be adjusted without a major disassembly of thevalve, and whereby the valve has backup protection to assure the safetyin the function of the valve system components.

It should be clear at this point that an inexpensive tamper proof safetyrelief valve has been provided which has an added tamper proof safetyvalve capability which is especially useful for installation ininaccessible areas where a high degree of reliability is required. Oneembodiment has been disclosed, but it should be clear that otherembodiments are contemplated as being within the spirit and scope of thepresent invention and that the valve can be made of any material such asstainless steel or other non-corrosive metals, as well as ferrous ornon-ferrous metals, plastics, synthetics, or any combination of thesematerials, and can be adapted to any particular users specificapplication.

Accordingly, the present invention is not to be construed as limited tothe particular forms disclosed herein, since these are to be regarded asillustrative rather than restrictive.

I claim:

1. A relief valve apparatus comprising:

a. a casing having an inlet and an outlet with a passagewaytherebetween;

b. a first valve gate positioned in said passageway, said first valvegate having a removable spring holding member;

c. a first coil spring biasing said first valve gate, one end of saidspring engaging said removable spring holding member whereby said firstvalve gate is adapted to open upon a first predetermined pressure beingapplied through said inlet against said first valve gate;

d. an adjustment member engaging said spring and threaded through anopening in said casing so as to facilitate adjustments to thecompression of said first coil spring and thereby select said firstpredetermined pressure;

e. a second valve gate positioned within said first valve gate;

f. a second coil spring positioned within said first valve gate forbiasing said second valve gate, whereby said second valve gate isadapted to open an alternate passageway between said inlet and saidoutlet and through said first valve gate upon a second predeterminedpressure greater than said first predetermined pressure being appliedthrough said inlet and against said second valve gate;

. a second valve gate adjustment cap disposed within said first valvegate and underneath said removable spring holding member, with one endof said second coil spring biased against said adjustment cap so as tofacilitate adjustment to the compression of said second coil spring andthereby select said second predetermined pressure; and wherein h. saidcasing and said first valve gate are closed such that access to suchsecond valve gate adjustment cap is had only by removal of said engagingmember, said first coil spring and said removable spring holding member.

1. A relief valve apparatus comprising: a. a casing having an inlet andan outlet with a passageway therebetween; b. a first valve gatepositioned in said passageway, said first valve gate having a removablespring holding member; c. a first coil spring biasing said first valvegate, one end of said spring engaging said removable spring holdingmember whereby said first valve gate is adapted to open upon a firstpredetermined pressure being applied through said inlet against saidfirst valve gate; d. an adjustment member engaging said spring andthreaded through an opening in said casing so as to facilitateadjustments to the compression of said first coil spring and therebyselect said first predetermined pressure; e. a second valve gatepositioned within said first valve gate; f. a second coil springpositioned within said first valve gate for biasing said second valvegate, whereby said second valve gate is adapted to open an alternatepassageway between said inlet and said outlet and through said firstvalve gate upon a second predetermined pressure greater than said firstpredetermined pressure being applied through said inlet and against saidsecond valve gate; g. a second valve gate adjustment cap disposed withinsaid first valve gate and underneath said removable spring holdingmember, with one end of said second coil spring biased against saidadjustment cap so as to facilitate adjustment to the compression of saidsecond coil spring and thereby select said second predeterminedpressure; and wherein h. said casing and said first valve gate areclosed such that access to such second valve gate adjustment cap is hadonly by removal of said engaging member, said first coil spring anD saidremovable spring holding member.